1. Field of the Invention
This invention relates to improvements in fiber optic image transmitting devices and has particular reference to the enhancement of images transported thereby.
2. Discussion of the Prior Art
Bundles of optical fibers having their opposite ends arranged in identical geometrical patterns provide image transmitters which transport image-forming light according to the well-known principles of total internal reflection. The tightness of fiber packing and particular patterning of ends of the fibers, their diametral sizes and cladding thicknesses as well as fiber breakage and transmission variations individually and/or collectively affect resolution of transported images in both rigid and flexible bundles.
In recognition of the need to overcome image degradation resulting from fiber core spacing and occurrences of fiber breakage or blemishing by gas bubble or foreign matter inclusions, dynamic image enhancement schemes have been devised to integrate non-conducting or partially conducting fibers and spaces therebetween with the overall patterning of ends of the transporting bundles. The theory of dynamic scanning is explained in the Journal of the Optical Society of America, Volume 47, No. 5, May, 1957, pages 423-427 and also in the New York Academic Press, 1967, pages 88-99.
Presently used dynamic scanning systems, however, suffer from problems of ungainliness, complexity and high cost. At best they lack a compactness desired in the medical profession and segments of industry employing small varieties of fiberscopes. U.S. Pat. Nos. 3,016,785; 3,217,588; and 3,217,589 exemplify the complexity and ungainliness of early fiberscope dynamic scanning systems.
More recent systems accomplish image enhancement with oscillating glass plates or short optical fiber bundles positioned between the fiberscope objectives and fiber bundle image-receiving ends. U.S. Pat. Nos. 4,141,624 and 4,154,502 illustrate these systems. This inclusion of image-oscillating means between objective lenses and image-receiving fiberscope ends, however, defeats the distal compactness in endoscopes which can be accomplished with short-focus objectives.
Accordingly, an object of the present invention is to accomplish greater than usual distal compactness in fiber optic endoscopes employing dynamic image enhancement means, particularly in the smaller varieties of medical and industrial devices.
Another object is to accomplish the above with novel wide angle objective lens means and minimal aberration.
Other objects and advantages of the invention will become apparent from the following description.